On Thu, Jul 26, 2012 at 7:57 PM, Arik Nemtsov <arik@xxxxxxxxxx> wrote: > On Thu, Jul 26, 2012 at 7:31 PM, Thomas Huehn > <thomas@xxxxxxxxxxxxxxxxxxxxxxx> wrote: >> Hi Johannes, >> >> Johannes Berg schrieb: >> >>>> >>>> /home/johannes/sys/wireless/drivers/net/wireless/ti/wlcore/tx.c: In >>>> function ‘wl1271_skb_queue_head’: >>>> /home/johannes/sys/wireless/drivers/net/wireless/ti/wlcore/tx.c:622:48: >>>> warning: ‘hlid’ may be used uninitialized in this function >>>> [-Wuninitialized] >>> >>> Those changes make no sense anyway -- you should be able to pass the >>> station pointer through if it previously used info->control.sta, instead >>> of doing an (expensive) lookup. >> >> >> This is the call path >> >> in main.c ... INIT_WORK(&wl->tx_work, wl1271_tx_work); >> jumps to tx.c...wl1271_tx_work(struct work_struct *work) >> calls wl1271_tx_work(struct work_struct *work) >> calls wlcore_tx_work_locked(struct wl1271 *wl) >> calls wl1271_skb_queue_head() >> calls wl12xx_tx_get_hlid() >> calls wl12xx_tx_get_hlid_ap() .... where sta is needed. >> >> But I could not find any point in the call path where I could grab the >> sta pointer and pass it through. I will move the rcu into >> wl12xx_tx_get_hlid_ap(), but I do not see any cheaper way here as using rcu. > > I agree with Johannes. The find_sta() in the Tx path is unacceptable. > > A relatively simple change here would be to put the sta pointer in the > portion of the struct reserved for rate control during op_tx(). wlcore > doesn't use software rate control anyway. > This would avoid from changing the code too much. Johannes correctly pointed out that the sta may no longer be valid when the skb is dequeued (which is a bug today as well). It's best to just store the hlid in the rate control portion. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
